Apparatus and method for filling syringe barrels

ABSTRACT

Apparatus for filling syringe barrels ( 1 ) with a product (A, B), includes at least one vacuum unit, at least one filling device, and a metering head ( 10 ) which can be moved with respect to the syringe barrel ( 1 ). The metering head ( 10 ) has a first material inlet valve ( 11   a ) and a second material inlet valve ( 11   b ) as well as a first vacuum valve ( 20   a ) and a second vacuum valve ( 20   b ). The material inlet valves ( 11   a,    11   b ) and the vacuum valves ( 20   a,    20   b ) are connected to channels ( 25   a,    25   b ), to each of which a chamber ( 2   a,    2   b ) of the syringe barrels ( 1 ) can be connected, as a result of which the syringe barrel ( 1 ) can be filled through the same openings ( 5   a   , 5   b ) as those through which the product (A, B) can be forced out of the chambers ( 2   a,    2   b ) by pistons ( 3 ) for use of the product, where the pistons ( 3 ) are inserted into the syringe barrels ( 1 ) before the barrels are filled.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The invention pertains to an apparatus for filling syringe barrels including a vacuum unit, a filling device, and a metering head which can be moved relative to the barrel. The invention also relates to a method for filling the barrel using the apparatus.

2. Description of the Related Art

Apparatus and methods of this type are suitable for filling syringe barrels with, for example, high-viscosity products.

An apparatus and a method of this type are known from DE 43 20 098 A1. Pharmaceutical or other products, especially those of high viscosity, are introduced into the syringe barrel under the application of a vacuum. Then a piston, which can be used later to force the product out, is inserted into the barrel. The insertion of the piston is also carried out under vacuum. How exactly this is done, however, remains unclear; that is, it is not explained how, within the scope of series production, the individual pistons are brought into position and how they are inserted into the syringe barrels.

When the piston is inserted into a syringe barrel which has just been filled with product, it is obvious that some of the product must be displaced from the barrel again. What happens to this displaced product and how contamination-free handling is possible cannot be derived from the document. Nor can it be seen how the piston is introduced into the syringe barrel.

SUMMARY OF THE INVENTION

The invention is based on the task of simplifying the process of filling syringe barrels.

The apparatus according to the invention is used for filling first and second syringe barrels having respective first and second pistons which are inserted into the barrels prior to filling, and respective first and second openings through which the barrels are filled with product and through which product is discharged. The apparatus includes a metering head having first and second channels which can be connected to respective first and second openings; first and second material inlet valves connected to respective first and second channels for filling respective barrels with first and second products; and first and second vacuum valves connected to respective first and second channels between said material inlet valves and the barrel openings.

In use, the first and second channels are connected to respective first and second openings, and a vacuum is drawn in the channels via the first and second vacuum valves so that the pistons are drawn into the barrels. The vacuum valves are then closed, and the material inlet valves are opened to fill the barrels with product from first and second supply tanks via the first and second inlet valves so that the pistons are displaced in the barrels. The positions of the pistons are detected by means of plungers which operate respective first and second proximity switches, and the material inlet valves are closed in response to signals from the proximity switches.

The various features of novelty which characterize the invention are pointed out with particularity in the claims annexed to and forming a part of the disclosure. For a better understanding of the invention, its operating advantages, and specific objects attained by its use, reference should be had to the drawing and descriptive matter in which there are illustrated and described preferred embodiments of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a diagram of a filling apparatus; and

FIGS. 2 a-2 c show details of a syringe barrel in the various phases of a filling operation.

DETAILED DESCRIPTION OF THE PRESENTLY PREFERRED EMBODIMENTS

FIG. 1 shows a syringe barrel 1, which has a first chamber 2 a and a second chamber 2 b. The chambers 2 a and 2 b are then filled with the products. In the exemplary embodiment, two chambers 2 a and 2 b are present because the syringe barrel 1 is intended to hold two different products, which are to be mixed together later for use. The products can be, for example, the two components of a two-component adhesive. The first component, therefore, is filled into the first chamber 2 a, and the second component is filled into the second chamber 2 b. A piston 3 is inserted into each of these two chambers 2 a, 2 b. By means of seals 4, the pistons close off the chambers 2 a, 2 b in leakproof fashion. Each seal 4 is illustrated schematically as an O ring. Normally, however, double-lip seals are used in syringe barrels of this type. The chambers 2 a, 2 b can be filled through openings 5 a and 5 b, through which the product can also be forced out of the chambers 2 a, 2 b by the pistons 3 for use. According to the invention, therefore, the pistons 3 are inserted even before the barrels are filled, which means that the delicate operation of inserting the pistons 3 into the syringe barrels 1 after they have been filled is eliminated.

Thus, according to the invention, the syringe barrel 1 is filled from the same end as that from which it will be emptied later during use. Thus, for the filling operation, there is no need for sealing parts such as a caps or plugs to seal tightly the opening opposite the filling end during the filling process described in DE 43 20 098 A1.

For the purpose of filling, the syringe barrel 1 can be placed on a metering head 10. This metering head 10 contains a first material inlet valve 11 a and a second material inlet valve 11 b. These two material inlet valves 11 a, 11 b can be actuated pneumatically, for example. From the material inlet valves 11 a, 11 b, product lines 12 a, 12 a lead to pressure vessels 13 a, 13 b, in which supply tanks 14 a, 14 b are provided. Products A and B, that is, the two components to be filled into the barrels, are held in these two supply tanks 14 a, 14 b. A pressure-regulated system of compressed air 15 a, 15 b is provided for each of the two pressure vessels 13 a, 13 b.

The metering head 10 also contains a first vacuum valve 20 a and a second vacuum valve 20 b. These vacuum valves 20 a, 20 b can also be actuated pneumatically, for example. From each of the vacuum valves 20 a, 20 b, a suction line 21 a, 21 b leads to a vacuum vessel 22 a, 22 b. A vacuum pump 23 a, 23 b is connected to each of the vacuum vessels 22 a, 22 b. A single vacuum pump 23 could also be used instead of the two vacuum pumps 23 a, 23 b.

The second connections of the material inlet valves 11 a, 11 b and of the vacuum valves 20 a, 20 b are connected to channels 25 a, 25 b. A first channel 25 a connects the material inlet valve 11 a and the vacuum valve 20 a to the chamber 2 a of the syringe barrel 1, and a second channel 25 b connects the material inlet valve 11 b and the vacuum valve 20 b to the chamber 2 b of the syringe barrel 1. In terms of its construction, the device is advantageously designed so that the volume of the channels 25 a, 25 b is as small as possible.

It is advantageous to assign an adjustable plunger 30 to each piston 3 of the syringe barrel 1; each plunger cooperates with a proximity switch 31 (only one plunger and only one switch are shown). The function of these switches will be described further below.

Not shown is a holder for the syringe barrel 1, into which the barrel can be inserted. Not shown either is a transport device, by means of which the metering head 10 can be moved with respect to the syringe barrel 1 and thus lowered onto the syringe barrel 1. As a result, it is ensured through pneumatic control, for example, that the openings 5 a, 5 b of the syringe barrel 1 will be aligned precisely with the channels 25 a, 25 b. In terms of design, the man of the art in question is familiar with appropriate possibilities. For safety reasons, the entire device can be designed for two-handed control.

The device shown in FIG. 1 is operated as follows:

After a syringe barrel 1 has been positioned correctly under the metering head 10, the two vacuum valves 20 a, 20 b are opened, so that a vacuum of predetermined strength is created in the chambers 2 a, 2 b and in the channels 25 a, 25 b. A pressure difference thus acts on the pistons 3, so that the pistons are pushed into their uppermost position, unless they are already there to begin with. After a predetermined period of time such as 1 second, the two vacuum valves 20 a, 20 b are closed, and immediately thereafter the two material inlet valves 11 a, 11 b are opened. Because the pressure vessels 13 a, 13 b, in which the supply tanks 14 a, 14 b are held, are under a pressure of, for example, 2-6 bars, the two products A, B are simultaneously forced from the supply tanks 14 a, 14 b through the product lines 12 a, 12 b and the material inlet valves 11 a, 11 b into the channels 25 a, 25 b and onward into the chambers 2 a, 2 b. The pistons 3 are automatically displaced. Each piston 3 then strikes the plunger 30 assigned to it and moves it outward. With the help of the associated proximity switches 31, the material inlet valves 11 a, 11 b are closed independently of each other, either simultaneously or in succession. The two chambers 2 a, 2 b have now been filled with products A and B. The chambers 2 a, 2 b, however, are still at this point under the pressure which prevails in the pressure vessels 13 a, 13 b.

To prevent the products A, B from escaping and contaminating the area when the connection between the syringe barrel 1 and the metering head 10 is broken, the two vacuum valves 20 a, 20 b are opened briefly to reduce the pressure.

Then the metering head 10 is moved a short distance away from the holder carrying the syringe barrel 1. Between the chambers 2 a, 2 b and the channels 25 a, 25 b there is now a gap, into which air can enter. Then the vacuum valves 20 a, 20 b are opened again briefly. As a result, excess amounts of products A, B are suctioned out of the openings 5 a, 5 b. These excess amounts of products A, B are simultaneously suctioned out of the channels 25 a, 25 b and transported through the suction lines 21 a, 21 b back into the vacuum vessels 22 a, 22 b, where they collect at the bottom and in some circumstances can be used again later.

FIGS. 2 a-2 c show details of a syringe barrel 1 in various phases of the filling operation.

The syringe barrel 1 is shown in the lower part of all three figures. On top, i.e., at the end facing the metering head 10 (FIG. 1), the barrel has a neck 32 for each of the openings 5 a, 5 b (FIG. 1). A nozzle 33, which belongs to the metering head 10, can be inserted into the tip of this neck 32 (FIG. 1). One of these nozzles is connected to each of the channels 25 a, 25 b,

In FIG. 2 a, the nozzle 33 is seated with a sealing action in the opening of the neck 32. The upward-pointing arrow indicates that air is being drawn out of the space above the piston 3, which happens during the previously described step in which a vacuum is produced by the opening of the vacuum valves 20 a, 20 b. The piston 3 is drawn up as far as it can go.

FIG. 2 b shows the “filling” phase, i.e., the phase during which the material inlet valves 11 a, 1 b are open. Now the product A, B is forced into the space above the piston 3, which simultaneously is pushed downward. Here, too, an arrow indicates the delivery direction. The product A, B is also present in the nozzle 33, but this is not illustrated in FIG. 2 b for reasons of clarity.

FIG. 2 c shows the last step of the process, in which the excess product A, B is suctioned off. The nozzle 33 is pulled back slightly here, so that a gap is formed between the bottom end of the nozzle 33 and the sealing surface in the interior of the neck 32. During the suction process, again indicated by a straight arrow, air can enter between the neck 32 and the nozzle 33. The part of the product A, B located above the bottom edge of the nozzle 33 is suctioned off. It should therefore be obvious that it is advantageous for the volume of the spaces between the vacuum valves 20 a, 20 b (FIG. 1), the material inlet valves 11 a, 11 b, and the bottom edge of the nozzle 33 to be as small as possible, because then only a small amount of the product A, B will need to be suctioned off. The suctioning-off step is the last step of the filling operation for the syringe barrel 1.

The invention simplifies the filling of syringe barrels 1.

The invention is not limited by the embodiments described above, which are presented as examples only, but can be modified in various ways within the scope of protection defined by the appended patent claims. 

1. Apparatus for filling first and second syringe barrels having respective first and second pistons which are inserted into the barrels prior to filling, and respective first and second openings through which the barrels are filled with product and through which product is discharged, the apparatus comprising a metering head, the metering head comprising: first and second channels which can be connected to respective said first and second openings; first and second material inlet valves connected to respective said first and second channels for filling respective barrels with first and second products; and first and second vacuum valves connected to respective said first and second channels between said material inlet valves and said openings of said barrel.
 2. The apparatus of claim 1 further comprising means for actuating the material inlet valves and the vacuum valves pneumatically.
 3. The apparatus of claim 2 further comprising first and second plungers which operate first and second proximity switches in response to movement of said pistons, said switches being effective to close the inlet valves when the barrels are filled.
 4. The apparatus of claim 1 further comprising first and second chambers filled with said first and second products, said chambers being connected to said channels through said inlet valves.
 5. The apparatus of claim 1 further comprising first and second vacuum vessels connected to said channels through said vacuum valves.
 6. A method for filling first and second syringe barrels having respective first and second pistons which are inserted into said barrels prior to filling, and respective first and second openings through which the barrels are filled with product and through which product is discharged, the method comprising: providing a metering head having first and second channels, first and second material inlet valves connected to respective said first and second channels, and first and second vacuum valves connected to respective said first and second channels; connecting said first and second channels to respective said first and second openings; drawing a predetermined vacuum in said channels via said first and second vacuum valves so that said pistons are drawn into respective said first and second barrels; closing said vacuum valves after a predetermined time; opening said material inlet valves; filling said barrels with product from first and second supply tanks via said first and second inlet valves so that said pistons are displaced in said barrels; detecting the positions of the pistons by means of plungers which operate respective first and second proximity switches; and closing the material inlet valves in response to signals from the proximity switches.
 7. The method of claim 6 further comprising: opening the vacuum valves in order to reduce pressure in the barrels after the material inlet valves are closed; and closing the vacuum valves.
 8. The method of claim 7 further comprising: disconnecting the channels from the syringe barrels; and opening the vacuum valves. 